Refrigerating apparatus



Sept. 29, 1931. A, M, THOMSON 1,825,215

REFRIGERATING APPARATUS Filed Nov. 2,2, 1926 -Patented Sept. 29, 1'931 UNITED STATES 'PATENT oFFlc-E .ALFRED M. THOMSON, or NEWARK, NEW JERSEY, ASSIGNOR To JOSEPH MERCADANTE,

. or NEW YORK, N. Y,

BEFRIGERATIN'G APPARATUS Application led November 22, 1926. Serial No. 149,844.

This invention relates to a refrigerating system, and particularly to refrigerating systems of the compression type. One of the objects of the invention is to provide an improved control valve for regulating the'flow of refrigerant from the high pressure side of the System to the low pressure Side, and to provide improved fluid connections for conducting the refrigerant to the expansion chamber or refrigeration element. a

Refrigeration S stems of the compression type include a re rigeration element located in a cooling chamber and supplied with a liquid refrigerant such as sulfur dioxide, which upon changing to the gaseous state Within thefcooling element produces the desired cooling effect. The system includes a pump or compressor for compressing the gasified refrigerant, a condenser for cooling and liquefying the compressed refrigerant, and an expansion valve through which the refrigerant passes to the refrigeration element. It is desirable to arrange the means for compressing and liquefying the refrigerant in a chamber disposed in close proximity to the cooling chamber.

The so-called expansion valve, whichl regulates the flow of the refrigerant from the high pressure side of the s stem to the low pressure be side, may consist o a float valve arranged in such a manner that the level of the liquid refrigerant Within a suitable float chamber automatically regulates the passage of refrigerant through the valve to the low pressure side of the system. M invention contemplates the provision o an improved float valve which is characterized by the provision of a valve member cooperating with a removable valve seat. The removable valve seat is preferably arranged in Such a manner that it can be readily removed from the outside of the float chamber Without disturbing any of the fluid connections communicating with the float chamber. My invention may include a casing forming a float chamber and having an opening preferably atv one end thereof adapted to be covered by a closure plate which may form a Support for the valve member and the valve seat. The casing is preferably p rovided With an enlargement in the upper porvided for the purpose o exhausting the noncondensible gases from the ioat chamber. This feature is also of Value as a means for exhausting any air which may be trapped in the system when it is 'being charged with refrigerant.

After the refrigerant passes through the expansion valve, it flows into the expansion chamber 0r refrigeration element wherein it boils and becomes gasified, thereby producing a refrigeration effect within the cooling chamber. It is a' common experience to have some of the refrigerant commence to boil before it enters the expansion chamber; that is, the refrigerant has a tendency to boil Within the pipe leading from the expansion valve to the refrigeration unit. This is lobjectionable because itis desirable to have the refrigerant boil only Within the expansion chamber, in order that the refri eration effect will be produced at the desire point inthe system. Furthermore, if some of the refrigerantl boils before it gets to the expansion chamber, a coating of frost wlll form on the outside of the conduit leading to the expansion chamr. I have found that by usin a conduit of small cross-section and consi erable length, it is possible to introduce the liquefied refrigerant into the expansion chamber with su stantially all of the refrigerant in liquid form. Such a conduit of small cross-section and considerable length would offer great resistance to the flow of gaseous refrigerant. When it is noted that la given quantity of a. refrigerant such as sulfur dioxide occupies approximately 700 times as much space in the gaseous state as in the liquid state, it can be appreciated that a very small conduit may `be Isuitable lfor supplying sufficient 1i uid refrigerant at low velocity, Whereas t is conduit would be entirely inadequate to supply the same quantity of gaseous refrigerant Within the same period of time. In any event, it has been observed that Where such a small conduit is employed, there is practically no tendency for the refrigerant to become gasiied within the conduit. The conduit remains free from frost, and the gasification of the refrigerant takes place almost entirely within the expansion chamber.

The resistance offered by a small conduit to the flow of refrigerant through the same is such that the conduit acts as a pressure reduction device, that is, the pressure of the refrigerant at the deliverv end of the conduit is materially less than that at the intake end of the conduit. I have found that this effect is so pronounced that it is possible to eliminate the pressure reduction valve between the high pressure side of the system and the low pressure side. The small conduit is useful in conjunction with an expansion valve, however, because it prevents boiling of the refrigerant between the valve and the eXpansion chamber.

The various objects and advantages of my invention can be best understood by considering the following detailed description, which is to be considered in conjunction with the accompanying drawings, in which Fig. 1 is a vertical section view of the refrigeration system` embodying my invention;

Fig. 2 is an enlarged vertical section view of one embodiment of my improved float valve; and

Fig. 3 is an enlarged section view of one form of conduit suitable for introducing the refrigerant into the expansion chamber.

In the drawings, and more particularly in Fig. 1, the refrigerating system of the present invention has been shown installed in a domestic refrigerator of the conventional type. This refrigerator comprises a lower mechanism compartment or chamber 1 containing the compressing, condensing and expanding mechanism of the system, a cooling chamber 2 containing the refri eration element and a food chamber 3, the ood chamber and the cooling chamber being preferably connected by the passages 4 and 5 to permit the circulation of air therebetween, and being enclosed by suitable heat insulating walls 6. The lower compartment 1 is preferably provided with Ventilating openings 7 in the side walls thereof.

The refrigeration or expansion element, designated as a whole as R, may take any suitable form, and as shown comprises a tank or header 8 having connected thereto a plurality of tubular passages 9 surrounding the freezing compartments 10 in which liquids or foods may be frozen. The refrigeration element R is preferably sup orted from the upper wall of the cooling c amber 2 by the supporting bracket 11. An inlet pipe 12 and an outlet pipe 13 are connected to the element R through suitable valves 14 and 15, respectively, these pipes being connected to the compression and expansion apparatus as hereinafter described.

The compression and expansion apparatus, located in the lower chamber 1, comprises a suitable source of power such as a motor 16, directly connected to a compressor 17 through a shaft 18. The compressor may be of any suitable form, and as shown comprises a pump of the rotary or gear type. The outlet pipe 13 from the refrigeration elemgnt R is connected to the intake of the compressor 17, while the outlet of the compressor is connected to the condenser coils 19 which are cooled by air currents from a fan 20 mounted on the shaft 18. From the lower end of the condenser coils 19, a pipe 21 extends to the expansion apparatus, which will be hereinafter described, and thence the refrigerant cycle is completed by a connection between the outlet of the expansion apparatus and the intake pipe 12 of the refrigeration element R.

The expansion valve unit, which comprises an important feature of the present invention, is shown in an enlarged sectional View in Fig. 2. This Valve, designated as a whole as V, comprises a chamber 22 constructed of a suitable metal and having an enlarged and somewhat spherically shaped portion at one end thereof, the opposite end being provided with an opening which is closed by a removable head or plate 23. A relief valve in the form of a pet cock 24 is preferably secured in an opening at the upper side of the enlarged portion of the chamber 22. An inlet pipe connection 25 of any suitable construction is secured in an opening 26 in the upper wall of the chamber 22 at a point near the removable head 23 as shown.

In the preferred embodiment of the invention illustrated, the expansion valve proper is located at the outlet port of the chamber 22, and comprises a float operad needle valve. This valve and its operating mechanism are carried by the plate 23 in an enlarged portion thereof, and comprise a removable tubular valve seat .26 secured in an opening in the plate 23 by means of a tubular set screw or nipple 63, and a needle of valve member 29, slidably supported in alignment with the seat 28 in an inwardly projected extension 30 of the head 23. A valve chamber 31 is provided adjacent the inner end of the valve seat 28, and is connected to the interior of the chamber 22 by a downwardly disposed port 32, a screen 33 being preferably provided over this port to prevent the entrance of foreign matter into the valve mechanism. The float mechanism for operating the valve member 29 comprises a float 34 secured to the end of a lever 35, the opposite end of which is pivotaliy secured to a bracket 36, integral with or suitably secured to the head 23. A short lever 37 is suitably secured to the lever 35, and engages the inner end of the valve member 29 between two fixed collars 38 thereon. It will be evident that the lll opening of the expansion valve is dependent upon the level of the liquid within the chamber 22, rising of the liquid level within this chamber serving to lift the float 34 and so draw the valve member 29` away from the valve seat 28 to open this valve. With this arrangement, the refrigerant is permitted to pass from the valve unit V in the liquid state only, since when the liquid level drops below m a predetermined point, which point is above the valve port 32, the float 34 is lowered to a oint at which the valve member 29 is moved lnto contact with the valve seat 28.

An opening 39 is provided in the enlarged portion 27 of the head 23 in alignment with the valve seat 28, this opening being of a larger diameter than the seat 28 and the set screw 63, whereby the set screw and seat may be removed therethrough without disturbing gq, any of the pipe connections of the system. his opening 39 is normally closed vby a plug 40, a washer or gasket 41 being provided to insure a gastight closure.' A suitable outlet pipe fitting 42 is secured in an opening 43 communicating with the opening 39 at the outer end of the valve seat 28, the opening 43 extending at an angle to the axis of the seat 28, as shown. The head 23 may be secured to the chamber 22 in any suitable manner, a gasket 44 being preferably provided between the head and the chamber to insure a tight closure.

The pipe 21 is connected through a suitable T-fitting 45 to a pipe 46 connected to the pipe litting v25 at the inlet port 26 of the chamber 22, a valve 47 being provided in the pipe 46. From the T-fitting 45, a short pipe 48, having a valve 49 therein, leads to a second T- fitting 50. A pipe 51 leads from the outlet fitting 42 of the expansion valve unit V through a third T-fitting 5 tothe pipe 12 of the refrigeration element R, and the T-fittings 52 and 50 are connected by a short pipe 53 having a valve 54 therein. A pressure reduction coil 55 is connected to the T-litting through a check valve 56 of suitable design, the upper end of the coil being connected to the pipe12 leading to the refrigeration element R through a valve 57, as shown. A valve 58 is provided in the pipe 59 between the T-fitting 52 and the point at which the coil 55 is connected to the pipe 12.

The coil 55 preferably comprises a comparatively long pipe of very small diameter, a pipe approximately twenty feet long and one-sixteenth of an inch in diameter having been found suitable for this purpose when delivering refrigerant at the rate of approximately one-half cubic foot per'minute. The dimensions of the coil 55 are so arranged to prevent the boiling and gasifying of the refrigerant li uid as heretofore described, the long pipe o small diameter permitting the pressure of the liquid to be reduced at a very slow rate, and so maintaining the refrigerant in 1the liquid state as it passes through the co1 By the arrangement of the pipe connecj tions and valves described, the entire flow ofB the refrigerant may be diverted through either the expansion valve unit V or the coil 55, or the refrigerant may be caused to flow through the valve unit V and the coil 55 in series. For example, if it is desired to bypass the entire flow of the refrigerant around the coil 55 and through the expansion valve unit V, the valves 49, 54 and 57 are closed, and the valves 47 and 58 are opened, and with this setting of the valves, the refrigerant Hows from the pipe 21 through the pipe 46, the expansion valve unit V, and the pipes 51, 59 and 12 to the refrigeration element R. If it is desired to by-pass the entire How of refrigerant around the valve unit V and through the coil 55, the valves 47, 54 and 58 are. closed and the valves 49 and 57 are opened, the refrigerant then flowing from the pipe 21 through the T-fitting 45, the pipe 48, the T-fitting 50, the coil 55 and the pipe 12 to the vrefrigeration element Rl When it is desired to permit the refrigerant to flow through the expansion valve unit V and the coil 55 in series, the valves 49 and 58 are closed and the valves 47 54 and 57 are opened, With the valves arranged in this manner, the refrigerant first passes through the expansion valve V and then passes through the coil 55- where the pressure is gradually reduced and the liquid refrigerant' then passes under reduced pressure to the refrigeration unit R.

When the entire flow of refrigerant is diverted through the coil 55, a considerable back-pressure is built up in this coil, and when the compressor 17 is temporarily stopped, there is a tendency for'the refrigerant under this back-pressure to flow back through the pipe 21 and the condenser coils 19 and toy operate the compressor 17 backward, the refrigerant pressure in the coil 55 thus leaking off to the low pressure side of the system. In order to prevent this backing up of the refrigerant when the compressor 17 is stopped, the check valve 56 is provided at the lower or intake end of the coil 55, this valve permitting the refrigerant to flow from the pipe 21 to the coil 55, but preventing theV return flow of the refrigerant.

In order to further prevent the boiling or absorption of heat by the liquid refrigerant as it passes through the coil 55 and to the refrigeration element R, a special double walled conduit may be used in the construction of the coil 55 and the pipe connections described. A conduit of this type has been shown in section in Fig. 3, and comprises an inner tube or pipe 60 of comparatively small cross-section, surrounded by a larger pipe 61, which is preferably separated from the inner pipe by an air space 62, as shown. The air sys 4aus

space 62 between the pipes 60 and 61 forms an effective heat insulating jacket for the inner pipe 60, which carries the refrigerant. This form of double walled conduit is ordinarily employed in forming the coil 55,' and, if desired, this type of conduit may be employed in making all the pipe connections between the outlet end of the condenser coils 19 and the intake of the'refrigeration element R, thus effectively insulating the entire refrigerant feeding system against the absorption of heat.

The expansion apparatus of the present invention presents many advantageous features. By the use of the improved expansion valve unit V, the refrigerant is permitted to pass to the refrigeration element R in the liquid state only, and means are provided in the expansion valve unit for drawing off any air or non-condensible gases which may have become trapped in the system. The valve seat 28 of the needle valve in the unit V may be readily removed for cleaning or replacement by the removal of the plug 40, and this operation may be performed without altering the pipe connections of the system. The pressure reduction coil 55, connected to the expansion valve unit V through the pipe connections and valves as described, provides means for reducing the pressure of the refrigerant at any desired or suitable rate, and by the use of this combination of the coil and expansion valve, the refrigerant may be delivered to the refrigeration element without undue boiling or absorption of heat thereby.

Although the refrigerating system of the present invention has been described in connection with a single specific arrangement of devices and apparatus, it should be clearly understood that the invention is not l-imitezl to the exact means show-n, and that lertain changes, modifications and combinations may be made Without departing from the scope of the invention as defined by the appended claims.

I claim:

l. In a refrigerating apparatus, the combination of a cooling chamber, a refrigeration element therein, a second chamber located in close proximity to the cooling chamber, means within said second chamber for compressing and liquefying a gasified refrigerant. fluid connections for conducting the liquefied refrigerant to said refrigeration element, and a float valve for controlling the passage of liquid refrigerant to said element, the said fluid connections including a pipe extending betwen the valve and the said element vwith most of the pipe arranged within said second chamber, and the said pipe having a cross-section and length such that substantially all of the refrigerant passes into the refrigeration element in liquid form.

2. In a refrigerating apparatus, the combination of an expansion chamber, means for compressing and liquefying a gasified refrigerant, fluid connections for conducting the liquefied refrigerant to said expansion chamber, and a valve for controlling the passage of refrigerant to said expansion chamber, the said fluid connections including a doublewalled pipe communicating with the valve and with the expansion chamber, the said pipe having an air space between the walls thereof.

3. In a refrigerating apparatus, the combination of an expansion chamber, means for compressing and liquefying a gasified refrigerant, fluid connections for conducting the liquefied refrigerant to said expansion chamber, and a valve for controlling the passage of refrigerant to said expansion chamber, the said fluid connections including a doublewalled pipe communicating with the valve and with the expansion chamber, the said pipe having an air space between the walls thereof, and the cross-section and length of the inner wall being such that substantially all of the refrigerant is delivered to the expansion chamber in liquid form.

4. In a refrigerating apparatus, the combination of an expansion chamber, means for compressing a gasified refrigerant, and fluid connections for conducting the refrigerant to said expansion chamber, the said fluid connections including a double-walled pipe having an air space between the walls thereof, the cross-section and length of the inner wall being such that substantially all of the refrigerant is delivered to the expansion chamber in liquid form.

5. In a refrigeranting apparatus, the combination of a cooling chamber, a refrigeration elelnent therein, a second chamber in l close proximity to the cooling chamber, means within the second chamber for compressing and liquefying a gasified refrigerant, and a valve for controlling the passage of the refrigerant to said element, the said l fluid connections including a double-walled pipe having a air space between the walls thereof, the cross-section and length of the inner' wall being such that essentially all of the refrigerant is delivered to the refrigeration element in liquid form, and the said double-walled pipe being arranged with at least the major portion thereof within said second chamber.

6. In a refrigerating apparatus, the combination of an expansion chamber, means for compressing and liquefying a gasified refrigerant, fluid connections for conducting the refrigerant to said expansion chamber, a valve for controlling the passage of refrigerantto the expansion chamber, the said fluid connections including a pipe communicating with the valve and with the expansion chamber having a cross-section and length such that substantially all of the refrigerant is delivered to the eX ansion chamber in li uid form, and means or by-passing there rigerant around said valve.

7. In a refrigerating apparatus, the combination of an expansion chamber, means for compressing and liquefying a gasified refrigerant, fluid connections for conducting the refrigerant to said expansion chamber, a valve for controlling the passage of refrigerant to the expansion chamber, the said fluid connections including a pipe communicatin with the valve and with the expansion cham er having a cross-section and length such that substantially all of the reinigerant is delivered to the expansion chamber in liquid form, and means for ley-passing the refrigerant around said pipe.

8. In a refrigeratng apparatus, the combination of an expansion chamber, means for compressing and liquefying a gasified refrigerant, fluid connections for conducting the refrigerant to said expansion chamber and an expansion Valve for controlling the flow of liquid refrigerant from said compressing and liqueying means, the said 'fluid connections including a pipe of restricted bore eX- tending between said expansion valve and said expansion chamber, said pipe having a cross section and length such that substantially no gasification of the liquid refrigerant takes place between said expansion valve and said expansion chamber.

In testimony whereof I afix my signature.

ALFRED M. THOMSON. $5 

